Emergency power circuit with automatic switch-over - has batteries charged from mains providing power via oscillator, transformer and voltage regulator circuit

摘要

The emergency supply includes batteries which are normally charged from the mains, but which provide an oscillating circuit with power in case of mains failure. The supply includes four parts - the battery charger, control unit, power circuit and the stabiliser. The battery charger circuit includes a transformer and a diode and thyristor circuit providing DC. The control circuit comprises five integrated circuits controlling the operation of the power circuit - this in turn includes a transformer providing a 240 volt output. The power provided is regulated by a stabiliser having two symmetrical circuits including zener diodes to control the size of the positive and negative alternations of the output voltage. The circuit may be used to provide an uninterrupted supply to telephone equipment and control circuitry.